The present invention relates to improvements in plastic bags or pouches of the reuseable reopenable type and to a method of making wherein the pouches are formed as a double pouch with a double fastener strip between them.
In the manufacture of plastic bags and pouches with a plastic zipper opening such as used for foodstuffs or the like, different structures have been utilized. Such structures are illustrated in co-pending applications, Ser. Nos. 327,617, Filed Mar. 23, 1989, abandoned and continued as Ser. No. 579,284, Filed Sept. 7, 1990, now U.S. Pat. 5,002,781, Van Erden and U.S. Pat. No. 327,619, Filed Mar. 23, 1989, now U.S. Pat. No. 5,026,563, Van Erden et al. The present improvement relates to manufacture of bags of the type exemplified in the above patent applications wherein the bags are made as dual bags providing the advantages of increase in speed of manufacture and improvement of the security of attachment of the fastener strips to the bags.
In the structure of this type of bag, the bag is completely sealed against the ingress of air and moisture and seals so as to prevent the escape of liquid and greases such as often accompany foodstuffs. The bags are, however, openable by the user and resealable so as to protect the foodstuffs. The bags further have a tamper-evident feature so that the individual who purchases the bag with the product or foodstuffs from a store will visually be able to see whether access to the bag has been had previously. To accomplish these features, a unique form of structure must be employed and the present invention relates to an improved process for manufacture of that structure and further for the manufacture of the structure by producing dual bags in a single operation to thereby reduce the cost and speed the rate of manufacture.
It is an object of the present invention to provide an improved method and apparatus for the manufacture of dual bags of the type that are reopenable and have features to particularly accommodate the protection and handling of foodstuffs.
A further object of the invention is to provide an improved method and apparatus for the manufacture of dual reclosable bags wherein bonding of the layers is accomplished by heat sealing and bag and fastener areas are selectively heat bonded with means to uniquely prevent bonding in areas where the layers of film are to be left freely separable.
Other objects, advantages and features will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings in which: